My notes from a Mikuni seminar by Herb Kane

[SuperJETT]

Herb Kane is the guy behind the SBN carb, did most of the calibration (tuning, he called it calibration) for oem companies back then, and he gave a seminar back at the World Finals back in 95 or 96. Here are my notes off the SBN manual they handed us.

HP/10 = fuel flow required
110HP/10 = 11gph
H-series (regular SBN) = 35liters/hour = 9.24gph
I-series (Sea-doo) = 40liters/hour = ~110hp
(all of these are for 6000rpm, the fuel flow does increase fairly linearly above that)
smaller needle valve for high vibration (size doesn't matter really)
DF62 = 17gph

44's like total jets of 220-230 (low+high)
46's like 240
(these are for un-modified carbs only)

Anyway, that's what I have written. I wanted to save it for posterity since my manual is getting kinda dirty after sitting in the garage for 13 years now and the ink is fading.

Something else to add, if you are wondering if you're way off on jetting, close both low and high screws and take it out for a spin (you'll need a little throttle to get it started probably). That way, you're running on the fuel supplied by the jets only and will know pretty quickly if you're way off.

 

[chrisdoc0608]

for the jet total of 240 on the 46, is that for un-modified motors or does it make a difference?

 

[Moondance]

That's cool information. I am trying to learn about carbs & that puts some things into perspective for me. Thanks for sharing, Darin.

 

[SuperJETT]

for the jet total of 240 on the 46, is that for un-modified motors or does it make a difference?

Un-modified carbs, has nothing to do with the engine.

 

[Mouthfulloflake]

this is probably a dumb question..
but sitting here ( at work) without the manual in front of me, or the carb cutaway pic.

how does closeing the adjustor screws make it run ONLY fuel thru the jets?

( not arguing, I am ASKING..)


I have been told ( and beleive) the same about the needle size... just small enough to NOT vibrate and leak..

Herb Kane is the guy behind the SBN carb, did most of the calibration (tuning, he called it calibration) for oem companies back then, and he gave a seminar back at the World Finals back in 95 or 96. Here are my notes off the SBN manual they handed us.



Anyway, that's what I have written. I wanted to save it for posterity since my manual is getting kinda dirty after sitting in the garage for 13 years now and the ink is fading.

Something else to add, if you are wondering if you're way off on jetting, close both low and high screws and take it out for a spin (you'll need a little throttle to get it started probably). That way, you're running on the fuel supplied by the jets only and will know pretty quickly if you're way off.

 

[Mouthfulloflake]

EDIT.

I see now, the adjuster screws basically control the fuel thru a bypass in addition to the jet itself.

this is probably a dumb question..
but sitting here ( at work) without the manual in front of me, or the carb cutaway pic.

how does closeing the adjustor screws make it run ONLY fuel thru the jets?

( not arguing, I am ASKING..)



I have been told ( and beleive) the same about the needle size... just small enough to NOT vibrate and leak..

 

[Kaveman]

Darin it was 1995. I was at that same clinic. Did you win any of the give away items?

 

[SuperJETT]

Darin it was 1995. I was at that same clinic. Did you win any of the give away items?

Nope, just a free manual.

 

[showmepro1200]

Nope, just a free manual.

Is the SBN manual in your possession worth scanning in as a pdf file?? :biggthumpup:

 

[chrisdoc0608]

Is the SBN manual in your possession worth scanning in as a pdf file?? :biggthumpup:

its already in the tech faq i believe

 

[SuperJETT]

Is the SBN manual in your possession worth scanning in as a pdf file?? :biggthumpup:

Amazingly, Mikuni provides it for free.

http://www.mikuni.com/pdf/sbn_manual.pdf

Then, feel free to write the notes I posted above on the back cover and you have a reasonable facsimile of mine.

 

[showmepro1200]

Ah, I have that one - I thought what you had might be different.

 

[Matt_E]

Darin, the fuel flow figures.....are those constrained by the fuel pump or constrained by the carb fuel flow?

 

[SuperJETT]

Darin, the fuel flow figures.....are those constrained by the fuel pump or constrained by the carb fuel flow?

I'd say the pump unless you have a carb with modded circuitry like the older Novis that I think limits flow.

 

[Matt_E]

Sooo.......what about using one of the external high capacity pumps then?

 

[SuperJETT]

I just took the notes, I didn't give the lecture...

 

[ski4]

wow cool info thanks darin

 

[Mark44]

Interesting I just added up my 44 jetting and it is 225

Mark44

 

[SuperJETT]

Interesting I just added up my 44 jetting and it is 225

Mark44

Yeah, it's interesting that most people that have their carbs tuned well end up within his thumbrules. (for regular Mikunis)

 

[Kny21]

Does this rule of thumb matter between single & dual?